Efforts to allow people to return to their homes near a Sumatran volcano after months in evacuation centers proved deadly when the mountain exploded without warning a day after they went home.

Sixteen people perished when Mount Sinabung produced a series of blasts that showered villages, farms and trees with a thick, gray ash.

Local disaster officials said most of the victims were burned by lava bombs that fell on the village of Sukameriah.

It was inside a 3-mile danger zone around Sinabung’s crater where evacuees had not yet been told to return, but many locals have regularly gone back to check on their house and to tend to their crops.

Among the dead were a local television journalist and four high-school students and their teacher who had defied warnings and visited the mountain’s slopes to see the eruptions up close.

Sinabung has been erupting since September. Authorities had evacuated more than 30,000 people into cramped tents, schools and public buildings, where they have lived for months.

Experts had said the eruption was calming down and that those living around the 3-mile danger zone could go home. Prior to last September, Sinabung’s last major eruption had been in August 2010. Before that, it had been quiet for four centuries.